The present invention relates to an assembly for preventing a battery terminal from rotating with respect to the housing of the battery, and more particularly, to an assembly for locking a terminal of a metal gas cell, such as a nickel hydrogen battery, against rotation with respect to a container through which the terminal extends.
As employed in metal gas cells, an electrode plate stack is housed within a container holding fluid at an elevated pressure. Each end of the plate stack is connected to a separate elongated terminal by suitable leads. Each terminal exits the container at opposite ends thereof. A teflon compression feed through seal is conventionally positioned between the container and terminal to seal against fluid leakage. However, as assembled, the terminal is capable of rotating with respect to the container thereby exposing the leads, and accordingly the cell, to premature failure.
In an attempt to prevent terminal rotation, terminals have been provided with two substantially parallel surfaces at the unsecured end thereof and adjacent a threaded portion. Once a metal gas cell is assembled, a nut is mated with the threaded portion of a terminal and is torqued into contact with an insulative washer positioned between the nut and the container while the terminal is secured against rotation by engaging both surfaces with any suitable means, for example a wrench. However, excessive torque applied to the nut can cause damage to the leads and, the necessity of including such surfaces increases the length and weight of a metal gas cell. In addition, lack of adequate space in a confined area may hinder or prevent holding a terminal against rotation so as to connect a plurality of cells by means of bus bars and poses a safety hazard due to the possibility of a manually manipulated wrench accidentally engaging the terminals of two separate cells.
Accordingly, it is an object of the present invention to provide an assembly for preventing the terminal of a battery from rotating with respect to the housing of a battery which has a relatively simple construction, is lightweight, and can be releasably secured to the terminal and battery housing without damage thereto and does not necessitate increasing the length of terminal.
It is another object of the present invention to provide an assembly for locking the terminal of a metal gas cell against rotation with respect to the cell container which does not require the terminal to be secured against rotation during assembly.